Method for fabricating semiconductor device

ABSTRACT

According to one embodiment, a method for fabricating a semiconductor device includes performing a back surface processing to remove at least one of a scratch and a foreign material formed on a back surface of a substrate to be processed, a front surface of the substrate being retained in a non-contact state, contacting the back surface of the substrate to a stage to be retained, and providing a pattern on the front surface of the substrate by using lithography.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2012-035018, filed on Feb. 21,2012, the entire contents of which are incorporated herein by reference.

FIELD

Exemplary embodiments described herein generally relate to a method forfabricating a semiconductor device, the method providing a desiredpattern on a substrate by lithography.

BACKGROUND

A residual film or a concave scratch may be formed on a back surface ofa substrate to be processed which has been performed various processessuch as forming, etching or the like in an LSI production. When the backsurface of the substrate is fixed on a stage in lithography process, thesubstrate is distorted due to the residual film or the concave scratch.As a result, a flat standard surface cannot be formed on the surface ofthe substrate to deteriorate the lithography process. Therefore, solvingthe back surface of the substrate by a chemical solution has beenperformed.

On the other hand, as a silicon oxide film, a silicon nitride film orthe like is deposited on the back surface of the substrate, it isdifficult to collectively solve these films with high speed. Further,even if these films are collectively solved, a concave scratch isleaved.

Polishing the back surface of the substrate can be considered for amethod to collectively remove the residual film or the concave scratch.In the polishing, the back surface of the substrate, which is polished,is applied with polishing load 100-500 hPa, for example. Accordingly, asubstrate retaining mechanism is necessary to support the polishingload. It is desirable that a retaining plate is disposed at a surfaceside opposite to the surface to be polished.

When the back surface of the substrate is polished in a LSI production,the front surface with a LSI structure of the substrate is retained.Consequently, a fine LSI structure can be damaged or contaminated.

As another method for retaining a substrate, a method of holding only aside surface has been known. However, the substrate is distorted withincreasing the polishing load. Especially, distortion amount in a centerof the large scale substrate becomes large, therefore, polishing cannotbe effectively performed and is capable of relating to crystallinedefects or crack of the substrate. Furthermore, as the substrate ispolished with high speed, suitable polishing load is necessary.Accordingly, the retaining method fixing the side surface is not fit tothe polishing processing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart showing a fabrication process of a semiconductordevice according to a first embodiment;

FIGS. 2A, 2B are cross sectional views, each view showing a constitutionof a substrate processing apparatus using a static pressure bearingaccording to the first embodiment;

FIGS. 3A, 3B is a schematic view showing an effect according to thefirst embodiment;

FIG. 4 is a characteristic view showing the effect according to thefirst embodiment;

FIG. 5 is a flowchart showing a fabrication process of a semiconductordevice according to a second embodiment;

FIGS. 6A-6H are cross-sectional views showing processing steps accordingto the second embodiment.

DETAILED DESCRIPTION

An aspect of the present embodiment, there is provided a method offabricating a semiconductor device includes performing a back surfaceprocessing to remove at least one of a scratch and a foreign materialformed on a back surface of a substrate to be processed, a front surfaceof the substrate being retained in a non-contact state, contacting theback surface of the substrate to a stage to be retained, and providing apattern on the front surface of the substrate by using lithography.

The present Embodiments will be described below in detail with referenceto the attached drawings mentioned above. Throughout the attacheddrawings, similar or same reference numerals show similar, equivalent orsame components.

First Embodiment

FIG. 1 is a flowchart showing a fabrication process of a semiconductordevice according to a first embodiment. Here, a pattern is provided on asubstrate by photolithography using a mask.

A substrate performed forming a film, etching a film or the like is usedas a substrate to be processed before lithography (Step S1). Surfacesincluding a back surface of the substrate are polished (Step S2). In thepolishing, a scratch and a foreign material on the back surface areremoved by using a static pressure bearing in a state that the frontsurface of the substrate is retained as non-contact to a peripheryenvironment.

After Step 2, the back surface of the substrate is cleaned (Step S3).Furthermore, the back surface of the substrate is dried (Step S4). Thepolishing, the cleaning and the drying (S2-S4) are desired to beperformed in a same chamber.

After coating a resist on the front surface of the substrate (Step S5),a pattern exposure is performed by using a photo mask (Step S6). AfterS6, developing the substrate is performed to provide a resist pattern(Step S7).

The film to be processed is selectively etched by dry-etching using theresist pattern as a mask so that the film to be processed is etched as aprescribed pattern.

Next, the first embodiment is described in detail below.

Generating a failure due to a foreign material such as a residual filmor a dust is prevented before lithography. The foreign material isattached on the back surface of the substrate to be processed. In such amanner, back surface processing, polishing for example, is performed tothe back surface of the substrate between forming a film or etching afilm and patterning by lithography. The residual film, a scratch orconvexoconcave on the substrate can be collectively removed bypolishing.

When the substrate is polished, it is necessary to apply some extent ofpolishing load, 100-500 hPa for example, on the back surface of thesubstrate to be polished. As a substrate-retaining mechanism for thepolishing load, fix of an edge portion of the substrate may be used whenthe polishing load is comparatively low. On the other hand, the surfacecorresponded to the surface to be polished, on which lithography processis performed, can be retained by a static pressure bearing when thepolishing load is comparatively high. A pressure fluid is selected fromwater, organic solvent, liquid with an organic material and highpressure gas. Gas is desired as the fluid fed from the static pressurebearing which faces to the surface with devices. In a case of liquid,corrosion of a fine pattern may be caused in the production. Further,when drying the device surface contacted to liquid, some kinds ofdefects such as watermark, distortion of the pattern or the like can begenerated.

FIGS. 2A, 2B are cross sectional views, each view showing a constitutionof a substrate processing apparatus using a static pressure bearingaccording to the first embodiment.

FIG. 2A shows an example in which a static pressure bearing 20 islocated under a substrate to be processed 10. The static pressurebearing 20 includes an inlet pipe 21 for pressure fluid and a pocket 22for retaining the pressure fluid. The load applied to the substrate 10is accepted with the pressure fluid in the pocket 22 and a front surfaceof the static pressure bearing 20 overflowed from the pocket 22. Aretainer 23 which retains a side portion of the substrate 10 is providedat an upper side of the static pressure bearing 20. When the substrateprocessing apparatus performs polishing a substrate or the like, thestatic pressure bearing 20 is configured to move upward towards thesubstrate and to move downward after the polishing is finished. Insteadof the up-down movement, an up-down mechanism of the substrate 10 can beset.

A polishing head with a smaller diameter than a diameter of thesubstrate 10 is located at an opposed side to the substrate surface sideof the static pressure bearing 20. A processing member 26 constitutedwith, for example, a soft material such as a sponge, a non-woven cloth,a foamed poly-urethane or the like, or a polishing tape, and a holder 25holding the processing member 26 are set at a leading edge of thepolishing head. It is available that the holder 25 may be not set.Further, the polishing head is supported with a supporting body (notshown) and is configured to act rotation, orbital motion, up-and-downmotion and the like. In such a manner, the polishing head 24 with thesmaller diameter than the diameter of the substrate is configured topolish the total surface of the substrate. Furthermore, the polishinghead 24 is configured to touch the substrate 10 due to the load appliedthrough the supporting body.

When a polishing processing is performed, a polishing solution isprovided from a slurry supply pipe 27. When cleaning processing isperformed, a cleaning solution is provided from a cleaning solutionsupply pipe 28. Two-fluid jet nozzle or a mega-sonic cleaning nozzle canbe set at a leading edge of the cleaning solution supply pipe 28.Meanwhile, the nozzles can be located another portion. Pure water,solution added a surfactant, cleaning solution controlling pH or thelike is used as the cleaning solution. Meanwhile, a chemical solutiondiluted with another chemical solution or solvent can be used as thecleaning solution. One kind of cleaning solution may be used; however,two or more kinds of cleaning solutions may be used as an order orparallel usage. Furthermore, it is not restricted that the same pipe canbe used both the slurry supply pipe 27 and the cleaning solution supplypipe 28.

The retainer 23 is connected to a rotation mechanism (not shown) to beconfigured to rotate with a high speed rotation. In a case that solventor vapor with lower vapor pressure is provided on the substrate indrying, a supply pipe for the solvent or the vapor can be located.

In FIG. 2A, the back surface processing, the cleaning processing and thedrying processing are performed in a same chamber as an example.However, these processes can be performed in each chamber.

FIG. 2B shows an example as another processing apparatus. FIG. 2B showsan example in which the static pressure bearing 20 is located upper thesubstrate to be processed 10. A basic function of the apparatus in FIG.2B is the same as the apparatus in FIG. 2A.

In the polishing processing using the apparatus described above, apolishing portion, which is the processing member 26, is touched to thesurface to be processed, which is the back surface of the substrate tobe processed 10, to apply the polishing load onto the surface to beprocessed through the polishing portion. A member with suitable hardnessor material property for removing foreign materials and convexoconcaveis located on a surface of the polishing portion. A size of thepolishing portion and a number of the polishing portions are notespecially restricted. Not only polishing the back surface of thesubstrate but a bevel portion of the substrate can be polished. Thepolishing portion and the substrate in the processing may be rotatedwithout fixing.

When the polishing portion is touched on the surface to be processed,the removed foreign materials or reaction products in the processing canbe exhausted out of the substrate by providing liquid such as polishingsolution or pure water onto the surface to be processed. The polishingsolution with abrasive grains, the polishing solution without abrasivegrains, surfactant or the like can be used.

An amount of the polishing is dependent on the foreign materials, sizeof convexoconcave to be removed, and is desired to be set correspondingto a target value of a prescribed flatness of the substrate surface.Further, the amount of the polishing is necessary to be over 50 nm whenthe convexoconcave over 100 nm is completely removed. In this case, theamount of the polishing is set to be 50 nm when the convexoconcave below50 nm can be acceptable.

When the foreign materials are attached on the back surface of thesubstrate with less convexoconcave, effect of removing the foreignmaterials can be sufficiently obtained in the amount of the polishingunder a half size of the foreign materials. Furthermore, effect ofremoving the foreign materials can be obtained in a case that thepolishing is zero which is performed by only pure water used as thepolishing solution.

After polishing, the foreign materials and the reaction products, whichare removed, are cleaned to be reliably exhausted out of the substrate.In the cleaning, contacting approach having a cleaning solution and asponge brush, for example, or a non-contact approach can be used.Further, both the contacting approach and the non-contact approach canbe concurrently used. However, the substrate may be reverselycontaminated from the sponge brush or the like in the contactingapproach. Accordingly, the non-contact approach is desired to be used ina final stage.

Using not only pure water but chemical solution as the cleaning solutionderives high efficiency for removing an attachment such as a foreignmaterial, residue, a dust or the like on the surface to be polished. Asurfactant preventing the attachment from re-attaching, an additiveagent, a component controlling pH of the chemical solution, an additiveagent reacting with a polishing residue to solve or to form a reactionproduct with water solubility, a protective agent for a polishingsurface or the like can be used as a component of the chemical solution.Such the chemical solutions can be not only used in the process of thecontacting approach and the non-contact approach but also be providedbefore cleaning or after cleaning. Furthermore, the polishing surfacecan be finished as a clean state in a case that a chemical solution candissolves the polishing surface or the foreign material. When two-fluidjet cleaning, mega-sonic cleaning or the like is concurrently used withthe chemical cleaning, higher cleaning performance can be achieved ascompared to the substrate rinse with chemical solution.

When the two-fluid jet cleaning or the like is performed, movement orthe like of the jet nozzle between the center of the substrate withrotation and the periphery of the substrate is performed to irradiatethe jet stream or the like to the substrate surface. Pure water or thelike with high pressure vapor is sprayed in the two-fluid jet cleaning.However, water dissolved CO₂ gas or the like can be used alternately topure water. As the high pressure vapor, clean vapor without a fineparticle as possible is used. However, a kind of the vapor is notrestricted when safety is maintained such as air, nitrogen or the like.A flow rate of the liquid used in the two-fluid jet cleaning is suitablein a rage from several ml/min to several hundreds ml/min. A flow rate ofthe vapor is suitable in a rage from several tens l/min to severalhundreds l/min.

Finally, the substrate is dried by high speed rotation or lower vaporpressure vapor such as IPA or the like and is shifted to nextprocessing, resist coating and lithography.

An aspect of lithography according to the first embodiment accompanyingwith a comparative case is shown in FIGS. 3A, 3B. For simpleunderstanding, a resist 13 in the FIGS. 3A, 3B has been alreadypatterned, however, the resist 13 is really set to be entirely coated onthe substrate in exposure processing.

In the substrate 10 to be processed, a film to be processed 12 is coatedon a Si substrate 11. A resist 13 is coated on the substrate 10 to beprocessed. A mask 40 for photolithography in which a pattern composed ofCr formed on a surface of a quartz glass is disposed above the substrate10. A pattern of the mask 40 for photolithography is reduce-projectedwith light having mono-wavelength laser or the like from an upperportion of the mask 40 through a lens system 45. The back surface of thesubstrate 10 is contacted to a flat plane of the stage so that thesubstrate is retained on the stage 30 by electro-static chuck or thelike. In such a manner, the surface flatness of the substrate isretained.

As shown in FIG. 3A, the foreign material is removed from the backsurface of the substrate 10 so that the front surface of the substrate10 has flatness. Therefore, a mask pattern is precisely transferred onthe resist 13. This is because a concave scratch, residual film or thelike can be surely removed by polishing the back surface of thesubstrate before the lithography described above.

On the other hand, when the back surface of the substrate closelyattaches to a flat surface in a state where a foreign material 48attaches on the front surface of the substrate, the substrate isdistorted not to be able to retain flatness of the substrate as shown inFIG. 3B. Consequently, a pattern reduce-projected on the resist 13 losesshape, so that the pattern cannot be formed in subsequent processing.The same influence as the above case is generated where convexoconcaveof the substrate, scratch, surface roughness or the like, for example,not limiting the foreign material, is formed on the back surface. Backsurface processing on the substrate solves the problem according to thefirst embodiment.

An effect of the first embodiment is described in reference to FIG. 4.FIG. 4 shows a number of the defects over 80 nm after some kind ofprocesses to remove convexoconcave or the foreign materials of the frontsurface and the back surface of the substrate. A SiO₂ film with 200 nmthickness formed on a silicon wafer by CVD is used as the reference. Anumber of the defects on the SiO₂ film after CVD are represented as 100,further a number of the defects of each process are relativelyrepresented.

Chemical solution processing combined with diluted HF and alkalisolution after forming SiO₂ cannot decrease a number of defects butslightly increase the number of defects. This is because surfaceroughness of the film or the like is generated due to dissolution of theSiO₂ film by diluted HF to increase the number of the defects.

When a brush cleaning is performed, the number of the defects isdecreased by half, however, another half is leaved so that removingeffect cannot fully obtain.

On the other hand, when a polishing portion is pressed on the surface ofthe SiO₂ film by using only pure water without abrasive grain orchemical solution, successively cleaning by chemical solution andtwo-fluid jet nozzle cleaning are performed, the number of the defectsis decreased to tenth part of the defects according to the firstembodiment. The residual defects are slightly concave removed signaturesafter each foreign material is removed without a residue. Pressure bythe fluid is 100 hPa in the above case, the number of the defects isdecreased with increasing the pressure.

In a case that the polishing portion is pressed on the back surface ofthe substrate with feeding a slurry with abrasive grains, which has aneffect to flatten a surface of the foreign material, onto the surface ofthe SiO₂ film, successively the same cleaning is performed, defect zerois attained over 200 hPa of the pressure by the polishing portion. Inother word, surely removing the scratch or the foreign material on theback surface of the substrate by polishing can be confirmed.

According to the first embodiment, the back surface of the substrate 10is performed by the back surface processing in a state where the frontsurface side of the substrate to be processed 10 is retained by staticpressure bearing 20 before lithography using a mask 40. In such amanner, the concave scratch or the foreign material can be removedwithout damaging the pattern of the front surface of the substrate. Thefront surface side of the substrate is necessary to be held, forexample, when the back surface processing is performed to the backsurface of the substrate in halfway of the production on the substratewith a fine LSI structure on the front surface. In such a case, the fineLSI structure is probably broken. Therefore, the processing cannot beconventionally performed. As the static pressure bearing can retainwithout contacting to the fine LSI structure, the back surface of thesubstrate can be easily cleaned. Accordingly, flatness of the frontsurface of the substrate can be enhanced when the back surface of thesubstrate is chucked to a flat surface so as to be easily aligned infocusing of a lithography process. As a result, pattern process accuracycan be enhanced.

As the method can be performed by using a small area apparatus having apolishing head with a small diameter and collectively performed from thepolishing to the cleaning and the drying, so as to have highproductivity, low cost, saving space or the like as advantages.Furthermore, as the front surface side of the substrate retains by thestatic pressure bearing using pressure fluid, the processing solutioncannot inserted into the front surface of the substrate. Accordingly,the front surface contamination by the processing can be prevented.Using the static pressure bearing in the cleaning processing can preventthe cleaning solution from inserting the front surface side of thesubstrate and contaminating with the inserting.

Instead of photolithography using a mask for exposure, electron beamlithography in which directly pattern on the resist by using electronbeam can be performed as the lithography in the first embodiment.Furthermore, the method can be applied to imprint lithography using astampa. In imprint lithography, the stampa with a pattern is pressed onthe resist on the substrate in stead of steps 6, 7 in FIG. 1.

In such manners, removing the concave scratch or the foreign material toclean the back surface of the substrate without damaging the patternformed on the front surface of the substrate provides improvement onflatness of the surface of the substrate fixed the back surface of thesubstrate to the flat surface. Consequently, the same effect which meansenhancing pattern process accuracy can be obtained.

Second Embodiment

FIG. 5 is a flowchart showing a fabrication process of a semiconductordevice according to a second embodiment. Here, a pattern is provided ona substrate to be processed by nano imprint lithography (NIL) using astampa.

A substrate to be processed by forming a film, etching a film or thelike is used before lithography (S11). Surfaces including a frontsurface of the substrate to be processed are polished (S12). In thepolishing, a scratch and a foreign material on the front surface of thesubstrate are removed by using the static pressure bearing in a statewhere the back surface is retained as non-contact to an environment.

Specifically, the polishing portion is touched to the surface of thesubstrate and the polishing load is applied onto the surface to beprocessed through the polishing portion in a state where the backsurface side of the substrate is retained by the static pressure bearingusing the substrate processing apparatus described in FIG. 2, when thepolishing is performed in the state where the polishing portion istouched to the surface to be processed, liquid, slurry, pure water, orthe like is provided on the surface to be polished so that the removedforeign materials or reaction products during the processing can be toexhausted out of the substrate.

After polishing, the surface of the substrate is cleaned to surelyremove foreign materials or reaction products out of the substrate(S13). Subsequently, the substrate is dried by high speed rotation orlower vapor pressure such as IPA or the like (S14). The polishing, thecleaning and the drying are desired to be performed in a same chamber sothat attachment of new foreign materials on the cleaned surface or backsurface of the substrate is prevented.

Next, a resist is coated on the front surface of the substrate (S15),successively imprint processing using a stampa is performed to provide aresist pattern on the front surface of the substrate (S16).

The film to be processed is processed as a desired pattern byselectively etching the film to be processed on the substrate by dryetching using the resist pattern as a mask (S17).

A method of processing the back surface of the substrate beforelithography in the first embodiment described above. On the other hand,processing the front surface of the substrate, namely the front surfacewith devices including polishing is performed before lithography,especially, NIL processing according to the second embodiment.

When a foreign material is attached on the surface or in the underlyingfilm in NIL processing, damage of a stampa is generated to cause acontinuous pattern defect. Removing the foreign materials andflattening, in which the polishing is performed on the front surfacewith devices before lithography, can prevent the damage of the stampa inNIL processing so as to lead precisely forming a pattern by lithography.Furthermore, totally removing the foreign materials by the polishing canprevent at least the damage of the stampa in NIL processing.

Conventional CMP (Chemical Mechanical Planarization) processing can beused as the polishing processing to polish the surface with the devicesof the substrate in this method. The surface to be polished can beapplied to a polishing pad with providing liquid such as the polishingsolution or pure water in the first embodiment in the CMP. Anotherprocessing such as cleaning, drying or the like can be performedaccording to the processing flow as same as the first embodiment.

FIGS. 6A-6H are cross-sectional views showing processing steps accordingto the second embodiment (FIGS. 6A-6D) and a comparative case (FIGS.6E-6H).

In a case that NIL method is performed, a substrate to be processed 60,which is an underlying film 62 is deposited on a Si substrate 61, isprepared. After a resist 63 is coated on the substrate to be processed60, a stampa 65 is applied on the substrate to be processed 60.

When a foreign material is not attached on the back surface of thesubstrate as shown in FIG. 6A, the stampa 65 is pressed into the resist63 as shown in FIG. 6B. After curing the resist 63, a resist pattern isprecisely obtained as shown in FIG. 6C by unfixing the stampa 65 fromthe resist 63. The underlying film 62 is selectively etched by RIE orthe like using the resist pattern as a mask to obtain a desired patternas shown in FIG. 6D.

On the other hand, a foreign material 64 can be mixed onto or into thesurface or an inner portion, respectively, of the underlying film 62,the resist 63 or substrate 61 as shown in FIG. 6E. It is considered thatan attachment on the substrate 61, a dust generated during a filmformation process, a micro particle mixed into the resist 63, a foreignmaterial or contamination attached at storing, feeding or the like inthe processing steps as the foreign material 64. When a thin film isdeposited on the surface of the LSI device in the processing steps, asource gas in CVD and a target material including a source material isused. A source gas reacts to generate solid above the substrate in a CVDchamber, so that the solid attached on the surface of the substrate. Aproduct generated in sputtering is attached to an inner wall of thesputtering chamber which is removed to be attached on the surface of thesubstrate. Such the attachment fall down on the surface of the substratein initial stage or halfway stage, so that the attachment is embeddedinto the thin film.

When the stampa 65 contacts to the foreign material 64, the stampa 65 isdamaged to be broken as shown in FIG. 6F. As another case, the foreignmaterial 64 may cut into the stampa 65 to be fixed. Furthermore,patterning on the resist or the underlying film 62 can be prevented dueto residual foreign material 64 as shown in FIGS. 6G, 6H. The stampa 65is an original version as the patterning. Accordingly, the defect of thestampa 65 is transferred into subsequent patterns to cause a patterndefect when the stampa 65 has such the defect. Removing the foreignmaterial left on the surface of the substrate by polishing can preventthe generation of the pattern defects according to the embodiments.

Polishing the front surface of the substrate to be processed beforeimprint-lithography is capable of easily removing a concave scratch or aforeign material according to the second embodiment. In such a manner,pattern processing accuracy in imprint-lithography can be obtained andgeneration of damage on the stampa can be prevented before happens.Furthermore, as the back surface side of the substrate 60 retains by thestatic pressure bearing using pressure fluid when the surface of thesubstrate is polished, the processing solution cannot inserted into theback surface of the substrate. Accordingly, the back surfacecontamination by the processing can be prevented. Using the staticpressure bearing in the cleaning processing can prevent the cleaningsolution from inserting the back surface side of the substrate andcontaminating with the inserting. The back surface of the substratewithout contamination is greatly effective in imprint lithography, whenthe flatness of the front surface of the substrate is enhanced by fixingthe back surface of the substrate to a flat surface.

The polishing processing of the back surface of the substrate asdescribed in S2-S4 according to the first embodiment can be performedbefore the polishing processing of the front surface of the substrate asdescribed in S12 in the second embodiment. Cleaning and flattening atthe back surface side of the substrate can be attained in the aboveprocessing. Flattening the back surface of the substrate is especiallyeffective for imprint-lithography, because the flattening the backsurface of the substrate is related to flattening the front surface ofthe substrate in a case that the back surface of the substrate is fixedto a flat surface.

Modification

An embodiment is not restricted to the two case mentioned above.

In a state where a main surface side of the substrate is retained innon-contact, another surface of the opposed side of the substrate ispolished in the embodiments. However, the processing of the surface ofthe substrate is not necessary limited to polishing. Scrubbing by abrush, blowing fluid or the like may be used when these methods canremove a foreign material and a scratch on the surface of the opposedside to the main surface of the substrate. In this case, a liquidincluding fine abrasive grains mixed in gas is sprayed into thesubstrate to be processed with high pressure and high speed to processthe substrate to be processed, for example. This method is called wetblast technology. Abrasive grains with below several μm of a diametercan be used as the fine abrasive grains. Further, it is not restrictedto a static pressure bearing as retaining the surface of the opposedside of the substrate to be processed. A method of retaining the surfacewithout contacting may be suitable.

Lithography in the first embodiment is not restricted to photolithography mentioned above, electron-beam lithography or imprintlithography. Printed electronics, which provides a pattern by printingusing a printing solution mixed fine particles, can be applicable.Namely, various kinds of lithography techniques, each of which isrequired that the front surface of the substrate has higher flatness ina state where the back surface of the substrate touches to a flatsurface.

Slurry used in the processing a front surface and back surface of thesubstrate, or conditions of polishing amount, pressure in contacting orthe like can be suitably changed corresponding to specification. In asame fashion, chemical solutions or the like used in the cleaning can besuitably changed corresponding to specification.

Other embodiments of the present disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the disclosure disclosed herein. It is intended that thespecification and example embodiments be considered as exemplary only,with a true scope and spirit of the disclosure being indicated by theclaims that follow. The disclosure can be carried out by being variouslymodified within a range not deviated from the gist of the disclosure.

What is claimed is:
 1. A method for fabricating a semiconductor device,comprising: performing a back surface processing to remove at least oneof a scratch and a foreign material formed on a back surface of asubstrate to be processed, a front surface of the substrate beingretained in a non-contact state; contacting the back surface of thesubstrate to a stage to be retained; and providing a pattern on thefront surface of the substrate using lithography.
 2. The method of claim1, wherein removing the back surface of the substrate by a processingmember, polishing the back surface of the substrate by a processingmember or spraying a fluid onto the back surface of the substrate to beprocessed is used in the back surface processing.
 3. The method of claim2, wherein a sponge, a non-woven cloth, a foamed polyurethane, apolishing tape or a polishing member is used as a material of theprocessing member.
 4. The method of claim 1, wherein a static pressurebearing providing a fluid on the front surface of the substrate isconfigured to retain the surface of the substrate in the non-contactstate.
 5. The method of claim 4, wherein the fluid is selected one ofwater, organic solvent, liquid with organic material and high pressuregas, each of the fluid not having a contamination factor.
 6. The methodof claim 2, wherein the back surface processing is sliding theprocessing member while contacting the processing member to the backsurface of the substrate.
 7. The method of claim 6, wherein thesubstrate is pressed with a pressure of 100 hPa or more by theprocessing member in the back surface processing.
 8. The method of claim6, wherein the processing member having a diameter smaller than adiameter of the substrate is moved on the back surface of the substratein the back surface processing.
 9. The method of claim 1, furthercomprising: cleaning the back surface of the substrate and successivelydrying the back surface of the substrate, after the performing the backsurface processing and before the providing the pattern on the frontsurface of the substrate.
 10. The method of claim 9, wherein the staticpressure bearing providing the fluid on the front surface of thesubstrate is configured to retain the substrate when the performing theback surface processing and the cleaning the back surface of thesubstrate, and a retainer contacting to a side surface of the substrateis configured to be used to retain the substrate when the drying theback surface of the substrate.
 11. A method for fabricating asemiconductor device, comprising: performing a front surface processingto remove at least one of a scratch and a foreign material formed on afront surface of a substrate to be processed where a back surface of thesubstrate is retained in a non-contact state; contacting the backsurface of the substrate to a stage to be retained; and providing apattern on the front surface of the substrate by using imprintlithography.
 12. The method of claim 11, wherein removing the frontsurface of the substrate by a processing member, polishing the frontsurface of the substrate by a processing member or spraying a fluid ontothe front surface of the substrate is used in the front surfaceprocessing.
 13. The method of claim 12, wherein a sponge, a non-wovencloth, a foamed polyurethane, a polishing tape or a polishing member isused as a material of the processing member.
 14. The method of claim 11,wherein a static pressure bearing providing a fluid on the front surfaceof the substrate is configured to retain the front surface of thesubstrate as the non-contact state.
 15. The method of claim 14, whereinthe fluid is selected from water, organic solvent, liquid with organicmaterial or high pressure gas, each of the fluid not having acontamination factor.
 16. The method of claim 12, wherein the frontsurface processing is sliding the processing member while contacting theprocessing member to the front surface of the substrate.
 17. The methodof claim 16, wherein the substrate is pressed by a pressure of 100 hPaor more as the front surface processing.
 18. The method of claim 16,wherein the processing member having a diameter smaller than a diameterof the substrate is moved on the front surface of the substrate in thefront surface processing.
 19. The method of claim 11, furthercomprising: cleaning the front surface of the substrate and successivelydrying the front surface of the substrate, after the performing thefront surface processing and before the providing the pattern on thefront surface of the substrate.
 20. The method of claim 19, wherein thestatic pressure bearing providing the fluid on the front surface of thesubstrate is configured to retain the substrate when the performing thefront surface processing and the cleaning the front surface of thesubstrate, and a retainer contacting to a side surface of the substrateis configured to be used to retain the substrate when the drying thefront surface of the substrate.